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BMW 2008 335I Serpentine Belt failure, not what it seems

We recently had a customer bring in very nice looking 208 335I with a shredded serpentine belt.  Upon inspection we notice that part of the belt was still attached.  One of our ASE certified mechanics replaced the belt and properly 3ainstructed the customer that to avoid such mishaps they should follow the recommended maintenance schedule for the car.  This particular car had over 92,000 miles on it and with proper maintenance  this and other issues can certainly be avoided.  The customer thanked him paid his bill and was soon on his way.

Well, about a week later we got a call from the same customer informing us that the BMW 335I has stalled and won’t start.  With the help of AAA the car was soon at our shop for us to take a look.  There were no visible signs of damage, but the BMW 335I was showing all the signs of a skipped timing chain.  Upon further review the technician determined that the timing was the cause and began to investigate it.

After removing the valve cover he noticed a piece of the serpentine belt lodged around the timing chain.  Apparently when the belt tore apart a piece of it followed the conical shaped crank pulley into the engine.(see photo).  Since the timing chain is also located directly behind the conical shaped crank pulley the shredded serpentine belt found itself wrapped around the timing chain, which ultimately caused the timing chain to jump teeth.  For performance and 4cefficiency reasons this motor has very tight clearance between the valves and the pistons and it only takes a couple of teeth to cause catastrophic failure.  In this case the end result was bent valves and a trashed engine.  This customer is now looking at the cost of a new, used or rebuilt BMW335I motor plus lightly over 27 hours in labor to pull out and replace the engine.  He will be lucky if his total bill is under $8,000.  Unfortunately all of this could have been avoided if the manufacture’s maintenance schedule is followed.  The cost to swap out a serpentine belt is minimal compared the alternative.

Most of us are aware of the popular maintenance procedures to perform or get preformed on a regular basis.  Things like tire rotation and oil changes are most common.  Unfortunately some of the biggest are often missed or done inadequately.  These include:

Belt Replacement

Coolant Flush & Hose replacement

Top End Fuel injection cleaning

Brake Fluid flushing & replacement

Transmission fluid service

Holmes Autowork’s ASE certified mechanics visually inspect all hoses and belts when preforming routine maintenance.  A warn serpentine belt would of been easily noticed during such inspection. Following the manufacture’s recommended maintenance schedule is the simplest and least expensive way to keep your vehicle in top working order.

Holmes Autoworks is a family run business.  We consider our customers our partners.  Without them we wouldn’t be in business.  We treat them with respect and only recommend what is right for them and their auto. We welcome the opportunity to be of service to you and your family.  The set up an appointment please call 386-409-0222. Thanks for visiting and have a great day.

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